BUCHAREST - Temperatures across central and southwest Europe threatened to top 42 degrees Celsius (107 Fahrenheit) on Saturday in a heat wave that has killed nine people in Romania and caused havoc from Hungary to Greece.

While the region sizzled, parts of northern Europe shivered in unseasonably fresh weather and flash flooding forced Britain to call out its Royal Air Force to rescue hundreds of people stranded in central England.

Poland was hit by a tornado, which is rare in Europe. News channel tvn24 showed roofs ripped off farmhouses and barns and cars destroyed near the southern Polish city of Czestochowa on Friday night.

At least 7 people were injured and hundreds left without power.

"Suddenly I saw the trees outside swaying violently and looked out to see a brown funnel approaching. We all took cover just in time," one middle-aged man told tvn24.

In Romania, Health Minister Eugen Nicolaescu said two people had died in the last 24 hours as temperatures reached 40 degrees Celsius, raising the death toll this week to nine.

Meteorologists said temperatures could get even higher in Romania's southern regions on the Danube river border with Bulgaria, where forest fires have ravaged thousands of hectares (acres) of land.

Bulgarian government officials said Russia was sending an airplane that can carry up to 40 metric tons of water to join the operations to stop one huge fire in the southeast from spreading further.

The fire sent huge clouds of smoke and dust over a nearby city of Stara Zagora with authorities warning thousands of residents to keep their windows shut and only go out wearing masks or wet towels.

Dozens of children were forced to flee their summer camp near the Greek city of Corinth this week when a huge brush fire threatened to engulf their compound.

Greece has been badly hit by forest fires over the past month as it swelters in its hottest summer in more than a century. Three fire-fighters were killed in a blaze on the island of Crete.

In Britain, hundreds of motorists were stranded in their cars on a major highway on Friday after one of the biggest downpours of an already wet summer.

"We've seen a month's rainfall for July fall in day," said a Meteorological Office spokesman.

In central England, thousands of people were taken to emergency centers.

"We've rescued in excess of 100 people by air," a Royal Air Force spokeswoman said. "We've picked people out of rivers or who were stranded on bits of land cut off by water as well as rescuing people from caravan rooftops."

There appeared to be no immediate let-up in the waves of rain across northern Europe, nor in the heat wave further south.

In Hungary, the heat has caused disruptions on railway and tram lines as tracks and power lines were damaged by the heat.

But few in the crowd at a Rolling Stones concert in Budapest's main Puskas stadium complained on Friday as organizers sprayed water over them to keep them cool.